Clutch and brake mechanism



y 2 1944. w. J. PEETS ETAL I 2,348,025

CLUTCH AND BRAKE MECHANISM Filed April 19, 1941 2 Sheets-Sheet l m a Q L as 0 n ME n I N z i y 1944- w. J. PEETS ET AL 2,348,025

CLUTCH AND BRAKE MECHANISM Filed April 19,. 1941 2 Sheets-Sheet2 and / John Po/l w g4 Q Patented May 2, 1944 CLUTCH AND BRAKE MECHANISM Wilbur J. Peets, Elizabeth, and John Roll, Union, N. 1., assignors. to The Singer Manufacturing Company, Elizabeth, N. 3., a corporation of New Jersey Application April 19, 1941, Serial No. 389,286

1 Claim This invention relates to driving devices and more particularly to a unitary motor, clutch and brake arrangement which is particularly adapted for driving manufacturing types of sewing ,machines where frequent operation of the clutch and brake to start and stop the machines is necessary.

One of the objects of this invention is to provi improved means for cooling the clutch elem ts during the operation of the device.

Another object of the invention is to provide improved means for preventing the driven element of the clutch from engaging the driving element after the friction material interposed between the two elements becomes worn.

With the above and other objects in view, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of partshereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features 011 the invention and the advantages attained thereby will be readily understood by those skilled in the art.

Fig. 1 is a longitudinal sectional view taken through an electric transmitter having our improvements embodied therein.

i is the driving element or flywheel 2| which is secured to rotate with the shaft l3 by a key 22. Also carried by the shaft I! are the ball bearings 23 and 24, the inner race of these bearings being fixed to the shaft by the nuts 23 and 24', respectively, to prevent both lateral and rotary motion relative to the shaft. Slidably mounted Fig. 2 is a perspective view of the driven clutch element looking from the side which engages the driving element.

Fig. 3 is a perspective view of one of the removable and replaceable friction rings which are interposed between the driving and driven elements and also between the driven element and the brake.

In the embodiment of this invention selected for illustration, the frame of the transmitter is of hollow cylindrical form and comprises a motor field section III having the usual field core Ii carrying-exciting windings 12. The field frame section to is closed at one end by an end honnet l3, and the other end is closed by an end bonnet i4 formed with a laterally extending flange l5 which forms a covering for the flywheel and clutch mechanism. The end bonnets l3 and I4 are clamped to the field frame by means of bolts, one of which is indicated as I6 in the drawings.

Carried by the end bonnets l3 and M are ball bearings I l and I8 in which is joumaled the hollow motor shaft l9. One end of the shaft extends into the clutch housing, and fixed to it at a point intermediate the bearings I1 and i8 is a rotor 20 which may be of the ordinary squirrel cage type. Located within the clutch housing on the periphery of the outer race of the ball bearings 23 and 24 is the cup-shaped hub 25 of the driven clutch disk or element 26. The driven element 26 has a flange-like portion which is formed with smooth opposed faces 21 and 28 and has removably secured to it, by any suitable means, a pulley 29. Also carried by the transmitter frame is a brake holding member 30 which is adjustable to and from the driven element by It will be understood that the driven element 26 is moved or shifted, by the sewing machine operator between thedriving element and the brake by means of arod 3| which is actuated by a sleeve 32 having a steep. pitched thread 33. The sleeve 32 may be turned by a lever or any other suitable means. For a more detailed and complete description of the mechanism above described reference may be had to our Patent No. 2,274,457, dated February 24,

Interposed between the driving element 2i and the driven element 26 is a friction ring comprising a ring of resilient sheet-metal 35 which has cemented to one of its faces a clutch facing or ring of friction material 36 having a smaller outer diameter than the outer diameter of the metal ring 35 and is preferably made of cork or the like. When the clutch is slipped so that the machine will operate slowly, or when the machine is stopped and started every few seconds, the flange of the driven element 26 and the friction ring 36 generate heat and become hot thereby causing rapid disintegration of the friction ring. To avoid .this overheating, we have provided the driven element 26 with openings 39 (Fig. 2) which are arranged adjacent the hub and the facing 36 of the friction ring has been formed with radially arranged slots 31. The rotation of the friction ring causes the slots to act as a, centrifugal fan and draw air through the openings 39 and between the driving and driven elements to cool these elements, the air being discharged at the outer periphery of the friction ring. It will be understood that the friction ring for the brake is identical with that used for the driven element.

To avoid metal to metal contact between the driving element and the driven element after the clutch-facing has become worn, we have formed the interior bore of the hub 25 with a shoulder II which is arranged so that it will engage the outer race of the ball bearing 23 before the driven element will engage the metal ring 35, or in other words the distance between the outer race of the ball bearing 23 and the shoulder M is slightly less than the distance between the face 21 of the driven element and. the metal ring 35 which is fixed to the flywheel 2|. With this construction it will be obvious that the possibility of scoring the contactingface 21 of the driven element 26 is eliminated.

Having thus set forth the nature of the 111-;

- vention what we claim herein is:

10 rality of radially disposed slots extending only partially therethrough.

WILBUR J. PEETS.

JOHN ROLL. 

